Typical stud welding apparatus of the prior art include a stud welding gun having separate cables for supplying a welding current, electrical control signals, and other functions such as a gas conduit for supplying inert welding gas, pressure tubes for pneumatic controls, and tubes for feeding studs. Such prior art welding apparatus include the separate cables that are usually taped or otherwise bundled together with a thin sheath in a “cable package”. The bundled cables are inherently difficult to handle and manipulate and are prone to damage when used in a typical work environment where the cables are moved and exposed to hostile welding conditions with chafe, bend, twist, cut, heat, fire, welding spatter, stretch, whip, tear, wear and abrasion.
Additionally, a control cable associated with the bundle is typically much weaker than the larger welding current cable due to its smaller diameter and thinner jacket. As such, the control cable is subject to a shorter service life when exposed to the same wear and abrasion. Additionally, the end connectors for a control cable are also weaker than the connector for the welding current cable such that when an operator pulls or otherwise manipulates a cable the control cable is subject to failure due to the weaker connector. Furthermore, in a cable package for robotic applications, the control cable is typically run straight along side the power cable and air tubes. Rapid movement of the weld head exerts inordinate torsion and bending. The straight control cable does not contain slack to absorb the stretch and compression, causing pre-mature fatigue failure and loss of conductivity. Prior art cables that include a polyester gas conduit are typically not protected and are subject to collapse, melting or puncture. Downtime associated with unexpected cable failures can be very costly to a manufacturer.
There is therefore a need in the art for a stud welding apparatus having an improved composite cable eliminating the need for separately bundled cables, as well as provides an increased service life and reliability of a welding apparatus. Additionally, there is a need in the art for a composite cable that may be easily manipulated by an operator or a robot and has a high resistance to wear and tear, abrasion, and other factors such as external heat and operator abuse.